Question 16460
Since you want this in the form of y as a function of x, then y is the dependent variable and x is the independent variable.

First, solve your equation for y.

{{{(1/4)y + 3 = -5x}}} Subtract 3 from both sides.
{{{(1/4)y = -5x - 3}}} Multiply both sides by the multiplicative inverse of 1/4
{{{y = 4(-5x - 3)}}} Simplify.
{{{y = -20x - 12}}} Now replace y with f(x) since y is a function of x, y = f(x)
{{{f(x) = -20x - 12}}} This is your equation in function form.